Enum VerificationError 

#[non_exhaustive]
pub enum VerificationError {
    InvalidFormat(String),
    InvalidPaymentAmount,
    Early,
    Expired,
    ChainIdMismatch,
    RecipientMismatch,
    AssetMismatch,
    InsufficientFunds,
    Permit2AllowanceRequired,
    InvalidSignature(String),
    SimulationFailed(String),
    UnsupportedChain,
    UnsupportedScheme,
    AcceptedRequirementsMismatch,
    NonceAlreadyUsed,
    DuplicateSettlement,
    MemoMismatch,
    MemoInstructionCountInvalid {
        count: usize,
    },
    SettlementAmountExceedsPermitted {
        requested: String,
        authorised: String,
    },
    UptoFacilitatorMismatch {
        witness: String,
    },
    UptoUnauthorizedFacilitator,
    UptoAmountExceedsPermitted,
}

Verification-phase failures.

Returned when payload parsing, signature verification, or pre-settlement on-chain checks reject the request.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

InvalidFormat(String)

The payload JSON / binary format could not be parsed.

InvalidPaymentAmount

The payment amount is below the required amount.

For SVM exact, overpayment (actual >= required) is allowed per scheme_exact_svm.md §1.4; only underpayment maps here.

Early

The payment authorization is not yet valid.

Expired

The payment authorization has expired.

ChainIdMismatch

The chain ID does not match requirements.

RecipientMismatch

The payment recipient does not match requirements.

AssetMismatch

The token asset does not match requirements.

InsufficientFunds

On-chain balance is insufficient.

Permit2AllowanceRequired

Permit2 allowance is insufficient.

Clients receiving this should call approve on the token contract pointing at the Permit2 address and retry. HTTP transports map this to 412 Precondition Failed.

InvalidSignature(String)

The payment signature is invalid.

SimulationFailed(String)

Pre-settlement simulation failed.

UnsupportedChain

The chain is not supported by this facilitator.

UnsupportedScheme

The scheme is not supported by this facilitator.

AcceptedRequirementsMismatch

Accepted details diverge from declared requirements.

NonceAlreadyUsed

EIP-3009 nonce already consumed on-chain.

DuplicateSettlement

Attempted to settle a transaction whose payload was already processed.

MemoMismatch

Memo data does not match extra.memo.

MemoInstructionCountInvalid

Invalid number of memo instructions (spec requires exactly one).

Fields

count: usize

Observed number of memo instructions.

SettlementAmountExceedsPermitted

Resource server requested a settlement amount exceeding the signed maximum authorisation (upto scheme).

Maps to ErrorReason::InvalidUptoEvmPayloadSettlementExceedsAmount on the wire, which serialises as invalid_upto_evm_payload_settlement_exceeds_amount per x402 v2 spec.

Fields

requested: String

Amount the resource server asked to settle.

authorised: String

Maximum amount signed by the buyer.

UptoFacilitatorMismatch

witness.facilitator does not match any address known to the facilitator (upto scheme).

Buyer either signed with a stale paymentRequirements.extra.facilitatorAddress or attempted to bind the payment to a different facilitator instance. Maps to ErrorReason::UptoFacilitatorMismatch.

Fields

witness: String

EIP-55 checksummed witness.facilitator from the buyer’s signed payload.

UptoUnauthorizedFacilitator

On-chain proxy reverted with UnauthorizedFacilitator because the settle transaction was submitted from an address other than witness.facilitator (upto scheme).

Maps to ErrorReason::UptoUnauthorizedFacilitator.

UptoAmountExceedsPermitted

On-chain proxy reverted with AmountExceedsPermitted (upto scheme). Defence-in-depth signal: the off-chain pipeline should have caught this before submission.

Maps to ErrorReason::UptoAmountExceedsPermitted.

Trait Implementations

impl AsPaymentProblem for VerificationError

fn as_payment_problem(&self) -> PaymentProblem

Produces the canonical wire-level payment problem.

impl Debug for VerificationError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for VerificationError

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for VerificationError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<Error> for VerificationError

fn from(err: Error) -> Self

Converts to this type from the input type.

impl From<VerificationError> for FacilitatorError

fn from(source: VerificationError) -> Self

Converts to this type from the input type.